I'M LUKE TIPPLE, AND THIS IS YOUR "DAILY BITE."

SHARKS ARE LOOKING AND MORE LIKE GENETIC SUPERHEROES EVERY DAY.

NEW DISCOVERIES ARE BEGINNING TO REVEAL THE SECRETS

TO SHARKS' HEALING ABILITIES,

AND THEIR GENETIC CODE IS JUST THE BEGINNING.

♪♪

SHARKS ARE ESSENTIALLY MODERN-DAY, LIVING FOSSILS,

AND STUDYING THEM CAN HELP UNLOCK

THE EVOLUTION OF MAMMALS LIKE US.

INSIDE SHARKS ARE TINY MOLECULES

THAT TELL THE STORY OF HOW OUR IMMUNE SYSTEMS HAVE DEVELOPED

AND CHANGED OVER THE CENTURIES.

ONE THING THAT SHARKS HAVE MANAGED TO KEEP UNDERCOVER

IS THEIR INCREDIBLE ABILITY TO FIGHT OFF DISEASE.

NOW, REMEMBER, THESE GUYS HAVE BEEN AROUND

FOR A LONG, LONG TIME, WAY LONGER THAN US HUMANS.

BUT EVEN THOUGH WE ARE MAMMALS,

WE SHARE MORE SIMILARITIES WITH SHARKS THAN YOU MAY THINK.

AND DISCOVERING THE SECRETS OF THEIR GENETIC CODE

COULD ENHANCE OUR ABILITY TO CURE HUMAN ILLNESSES.

SCIENTISTS HAVE BEEN STUDYING SHARKS' BLOOD

TO GET A CLOSER LOOK

AND MAP OUT THE STORY OF THEIR IMMUNE SYSTEMS.

THE RESEARCH IS STILL YOUNG,

BUT WE KNOW THAT SHARKS HAVE THREE SPECIAL ANTIBODIES.

TWO OF THOSE WE SORT OF SHARE WITH SHARKS,

BUT THE THIRD IS TOTALLY UNIQUE.

NOW, LIKE US, SHARKS USE THESE ANTIBODIES

TO CLEAR OUT PATHOGENS -- THOSE ARE THE BAD GUYS.

BUT UNLIKE US, THEY'RE ABLE TO DO IT AT SUPERPOWER SPEEDS,

SORT OF LIKE A CERTAIN COMIC-BOOK MUTANT.

BUT NOT ALL OF SHARKS' SECRETS ARE HIDDEN IN THEIR BLOOD

AND ANTIBODIES.

♪♪

SCIENTISTS HAVE MAPPED OUT THE GREAT WHITE SHARKS' GENOME,

AND THEY'VE DISCOVERED THAT THEY'RE LOADED UP

WITH WHAT'S CALLED "JUMPING GENES."

THOSE ARE TINY GENETIC ELEMENTS THAT CAN HOP AROUND

WHEREVER THEY MIGHT BE NEEDED, INCLUDING REPAIRING DNA.

♪♪

SO, SURE, THEY HAVE SOME AMAZING DISEASE-FIGHTING BLOOD,

BUT IT'S LITERALLY IN THEIR DNA.

AND GREAT WHITES ARE MODERN-DAY PROOF OF SHARKS'

400 MILLION-YEAR-OLD GENETIC SUPERIORITY.

BUT SHARKS AREN'T COMPLETELY INVULNERABLE TO ILLNESS.

A BRAIN-EATING BACTERIA THAT'S COMMONLY FOUND IN FISH

HAS BEEN RECENTLY DISCOVERED TO AFFECT MULTIPLE SHARK SPECIES.

WE HAVE SHARK WEEK SCIENTIST MELISSA CRISTINA

MáRQUEZ HERE TO TELL US MORE.

HI. I'M MELISSA CRISTINA MáRQUEZ.

AND I AM A SHARK SCIENTIST.

NOW, ONE BIG MYTH THAT SURROUNDS SHARKS

IS THAT THEY'RE NOT VULNERABLE TO DISEASES,

AND THAT'S JUST NOT TRUE.

SHARKS, LIKE US, DO GET SICK, THEY DO GET CANCER,

AND, ACTUALLY, MOST RECENTLY,

THEY GET A BACTERIA THAT EATS THEIR BRAIN

AND ESSENTIALLY MAKES THEM INTO ZOMBIE SHARKS.

SO, IT'S CALLED "CARNOBACTERIUM,"

AND IT'S A BACTERIA FOUND NATURALLY

IN THE STOMACHS OF TROUT AND SALMON.

AND IT DOESN'T AFFECT US, SO DON'T WORRY ABOUT IT.

BUT WHAT SCIENTISTS BELIEVE IS HAPPENING

IS THAT THESE SHARKS THAT ARE SPECIFICALLY EATING

THESE ANIMALS ARE ACTUALLY INGESTING THIS BACTERIA

AND THEN PASSING IT TO ANY SHARKS THAT ARE IN UTERO,

SO, ESSENTIALLY, THESE SHARKS ARE BEING BORN

WITH THIS BRAIN-EATING DISEASE.

SO, WHAT HAPPENS IS, IS THAT THE BACTERIA CRAWLS

INTO AN ORIFICE OF THE SHARK

AND ESSENTIALLY STARTS MUNCHING AWAY AT THE SHARK'S BRAIN,

TURNING THEM INTO A ZOMBIE

BECAUSE THEY HAVE NO IDEA WHAT THEY'RE DOING WHATSOEVER.

AND IT CONTINUES BEACHING ITSELF UNTIL IT EVENTUALLY DIES.

AND IT'S NOT JUST ONE SPECIES OF SHARK --

YOU'VE GOT THIS HAPPENING IN MAKO SHARKS,

IN THRESHER SHARKS, AND EVEN BASKING SHARKS,

AND SOME OF THEM ARE ACTUALLY WASHING UP ONSHORE

IN CALIFORNIA.

SO, LIKE MANY THINGS IN SHARK SCIENCE,

WE DON'T HAVE ALL THE ANSWERS.

WE'RE STILL TRYING TO FIGURE OUT WHAT'S GOING ON.

BUT THAT'S ONE REALLY COOL THING

THAT YOU MIGHT NOT KNOW ABOUT SHARKS IS THAT

THEY'RE JUST AS VULNERABLE AS WE ARE TO DISEASES,

BUT MAYBE NOT WITH SHARK-EATING, BRAIN-EATING BACTERIA,

SO DON'T WORRY ABOUT THAT.

SHARKS STILL CLEARLY HAVE A TON TO EACH US,

SO IT'S INCREDIBLY IMPORTANT THAT WE KEEP THEM AROUND.

THEY ARE EXCELLENT AT ADAPTING.

THE PROOF IS CERTAINLY OUT THERE --

400 MILLION YEARS AND COUNTING.

AND HUMANS HAVE ONLY BEEN AROUND A FRACTION OF THAT TIME,

AND WE'VE MANAGED TO MAKE OURSELVES SHARKS' GREATEST ENEMY

WHEN WE OUGHT TO BE TREATING THEM

LIKE THE GREATEST ASSET TO OUR OWN SPECIES' SURVIVAL.

STICK WITH US ALL SHARK WEEK LONG AS WE CONTINUE

TO BRING THE MOST JAW-DROPPING DISCOVERIES IN SHARK.

IN THE NEXT EPISODE OF THE "DAILY BITE,"

WE'RE TALKING TO THE SHARK PAPARAZZI.